WASHINGTON ― Just hours before an expected Thursday vote in the House, congressional Republicans are considering massive changes to insurance coverage without even a basic idea of what those changes would mean.

According to House Freedom Caucus members, the conservative group is negotiating directly with President Donald Trump and the White House on an amendment to the Republican health care bill, seemingly cutting out GOP leadership from the conversation as Speaker Paul Ryan (R-Wis.) and his deputies work to corral votes for a bill that is, in these latest provisions, a mystery even to them.

The re-opening of negotiations is an admission of what has been clear all along ― that the bill as constructed by Ryan does not have the votes to pass on Thursday. It also represents a major reorganization of a significant chunk of the American economy in a matter of hours.

Conservatives are using their considerable leverage on the measure ― the Freedom Caucus has demonstrated it has the votes to sink the legislation ― to extract concessions on the Essential Health Benefits section of the bill, which mandates that insurers offer plans covering 10 services: outpatient care, emergency room visits, hospitalization, maternity and newborn care, mental health and addiction treatment, prescription drugs, rehabilitative services, lab services, preventive care and pediatric services.

“Negotiations are taking place,” Freedom Caucus member Randy Weber (R-Texas) told reporters Wednesday night. Asked if he thought they were going to get to a deal, Weber said it sounded like it.

“The president’s moving our way,” he said.

While conservatives have been cagey about the offer from the White House, multiple Freedom Caucus members suggested Wednesday night that Trump has offered to eliminate the Essential Health Benefits portions of the Affordable Care Act ― potentially lowering premiums, but only by giving insurers incentive to drop expensive benefits that some people need. The exact effect of those changes remains unknown, as Republicans plan to vote without an updated score from the Congressional Budget Office on those modifications. But health experts generally agree it would not substantially lower premiums for most people, though it could raise prices for people who do need those services ― such as women who may need maternity care.

Freedom Caucus leaders, however, insist those changes are still not enough to win over most of their members. Conservatives in the group also want revisions to Title I of the ACA, which contains things like protections for people with pre-existing conditions. Although Trump has insisted he wants to keep those protections, the president has already shown a willingness to compromise on his promises. (Remember in January when he promised better and cheaper “insurance for everybody”? The CBO says the current health care bill would insure 24 million fewer people in 10 years, weaken coverage, and raise premiums on seniors.)

Thus far, the White House has not agreed to make the Title I changes that the Freedom Caucus wants, and it’s unclear how solid its offer to eliminate Essential Health Benefits really is. Republicans could add that language in the House to see it immediately stripped in the Senate, either by agreement or by a vote under the so-called Byrd rule, which subjects policy changes in a reconciliation bill to the normal 60-vote threshold in the Senate. But the offer has already softened some of the conservative opposition in the House.

Freedom Caucus Chairman Mark Meadows (R-N.C.) said the group was “encouraged” by the willingness of the White House to negotiate, and said he was “very optimistic” they could get to a deal before noon on Thursday.

“Honestly I have some work to do with some of my more moderate colleagues to make sure that whatever we do not only gets us to 218 or better in the House, but also gets us to 51 in the Senate,” Meadows said. “Those discussions are ongoing.”

As Meadows suggested, the changes conservatives want could cause moderates to abandon the bill en masse, not only in the House but also in the Senate, though the Freedom Caucus is counting on leadership to keep those House members in line. At this point, it’s unclear how moderates will react, in part because there’s still no deal or legislation to review.

In addition, there are still some conservatives, inside and outside of the Freedom Caucus, who seem prepared to vote against the bill even with a deal. Those members, who could range from somewhere near half a dozen to more than a dozen, could team up with moderates to sink the legislation even after leaders made those concessions to conservatives.

And then there are still questions about what it would take to get to a deal. The Freedom Caucus hasn’t agreed to just the Essential Health Benefits change, though leaders look apt to make that adjustment in a manager’s amendment to the legislation that hasn’t yet been released.

The Rules Committee is preparing a manager’s amendment for the legislation, and the changes conservatives want ― if a deal is reached ― are expected to be in that amendment. With the clock ticking on the Rules Committee, leaders may decide to add the Essential Health Benefits portion and dare the Freedom Caucus to vote against the bill.

Still, Meadows seemed to think conservatives were headed to a win on the bill.

“I don’t want to be so optimistic to say that the deal is done, but I do think that there is a framework to work with our leadership, and the leadership in the Senate, and certainly the administration to find some common ground,” he said.